An exemplary background art in the technical field is disclosed in Japanese Patent Application Laid-Open No. 2003-294606 (Patent Literature 1). The environmental assessment device disclosed in this literature basically includes 1) an element unit that reacts with a gaseous component in the environment, 2) a unit that detects the change of the element and converts the detected data into an electric signal, and 3) a unit that stores the measured data. The device employs, as the sensing element, thin metal films (thin metal films each having a thickness of 0.1 μm and being made of one of silver, copper, iron, and stainless steels). The device assesses an environment where a material is placed, by measuring a time-related change of at least one property, of the thin metal films, selected from optical reflectance, light transmittance, and electric resistance, and detecting a gaseous component in the environment. When the time-related change of the electric resistance is to be measured, the thickness of a corroded layer can be calculated, and thereby the corrosion rate can be easily determined, by measuring the change of the electric resistance caused by the change of the entire thin film (general corrosion).
A gas detecting system, which detects the change in the element and converts the change into an electric signal, includes a gas introducing unit and a gas sensing element unit (unit corresponding to a sensor unit in the present invention). The gaseous component is fed via a suction pump in the gas introducing unit to the gas sensing element unit. The technique can provide an analyzer that is very useful for environmental assessments for various materials, under circumstances where the global environment varies.